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Math Help - Trig question

  1. #1
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    Trig question

    If an earthquake has an intensity of x, then its magnitude, as compounded by the Richter Scale, is given by R(x) = log x/I sub 0, where I sub 0 is the intensity of a small measurable earthquake. (consider I sub 0 = 1 for this problem). If one earthquake has a magnitude of 4.4 on the richter scale and a second earthquake has the magnitude of 5.8 on the Richter scale, howe many times more intense (to the nearest whole number) is the second earthquake than the first?


    A) 6
    B) 15,848,931,925
    C) 25
    D) 21
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  2. #2
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    e^(i*pi)'s Avatar
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    Quote Originally Posted by cspan1986 View Post
    If an earthquake has an intensity of x, then its magnitude, as compounded by the Richter Scale, is given by R(x) = log x/I sub 0, where I sub 0 is the intensity of a small measurable earthquake. (consider I sub 0 = 1 for this problem). If one earthquake has a magnitude of 4.4 on the richter scale and a second earthquake has the magnitude of 5.8 on the Richter scale, howe many times more intense (to the nearest whole number) is the second earthquake than the first?


    A) 6
    B) 15,848,931,925
    C) 25
    D) 21
    There is no need to put font tags around all options - it just makes it harder to read. Also this is a log problem - trig isn't involved


    R_{1} = log(x_1) \: \: \therefore \: x_1 = 10^{R_1}

    R_2 = log(x_2) \: \: \therefore \: x_2 = 10^{R_2}

    Take the ratio of these

    \frac{x_2}{x_1} = \frac{10^{R_2}}{10^{R_1}}

    R_2 and R_1 are known and \frac{x_2}{x_1} is the ratio of intensity (the answer you want)
    Last edited by e^(i*pi); November 23rd 2009 at 11:25 AM.
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